Guide to Dog Ear Illnesses

Summary:

"Dog Ear Illnesses have many causes including:

Bacteria

Fungus or yeast

Changes in the structure of the ear

Parasites

Food or environmental hypersensitivity or allergy

Treatment errors

Symptoms are often described
as being Otitis Externa, which is inflammation of the external ear
canal
(includes the pinnae or ear itself, ear canals and external wall of the
tympanic membrane), or Otitis media, which is inflammation of the
middle ear. The middle ear includes the wall of the tympanic membrane,
bulla (tympanic cavity), auditory ossicles and the auditory tube.
If a dog has balance problems, vestibular disease can be the cause,
which is a problem in the inner ear and the way that information is
coordinated with other senses and communicated to the brain.

Dog Ear Anatomy

Inflammation in the ear is the result of a problem with the normal ear environment. For example enlarged glands
(the ear is lined with cerumen glands) or excessive wax can cause
inflammation. Problems in the middle ear often start in the outer or
external ear. Otitis externa is the most common diagnosis with bacteria
or yeast being the cause. The infection perpetuates the ear problem
and if not treated, can lead to changes that can affect ear health and
hearing.

Some breeds such as those with pendulous
ears (Spaniel and Retrievers), with hair lined ear canals (Terriers and
Poodles) or narrow ear canals (Shar pei) are prone to ear infections.
This is also true for dogs that live in humid climates. Treatment is
usually with select drops and antibiotics.

In some cases surgery is necessary to either
resolve a dog ear problem (tumors, injuries) or as a complement to the
use of medications.."

Overview

There are two main types of dog ear illnesses: infections of the
outer ear (otitis externa) and infections of the middle ear (otitis
media). Most ear illnesses begin in the outer ear and are caused by
either a bacterial or a fungal infection. Often only one ear is
affected. Infections may spread from the outer ear into the middle ear.
Improper cleaning or foreign bodies in the ear may rupture the ear
drum, also spreading infection to the middle ear.

Dog ear illnesses are first evaluate based on the probably cause of
the problem. This is based in part on the location of the problem on
the ears.

Location and Common Causes of Dog
Ear Illnesses

Breed

Location of Dog Ear Symptoms

Pinnae (part of the ear that
extends from the dogs body to the tip of the ear)

Ear infections may also be caused by ear mites (Otodectes
cynotis). Ear mites, when present, are generally present in
both
ears. They are easier to treat than many other types of infections. A
single cleaning with a medicated solution often does the trick. If your
dog has mites, be sure to clean the area he or she lives in with a
miticide such as Benzarid.

Breeds Prone to Dog Ear Problems

Some pets are more susceptible to dog ear illnesses than others. This
includes breeds with:

Pendulous ears

basset hounds

cocker spaniels

retrievers

Hairy Ears (Hirsute external canals)

Terriers

Poodles

Schnauzers

Narrow Ear Canals

Shar-pei

Common Dog Ear Illnesses

Common Dog Ear Illnesses

Causes

Description of Dog Ear Problem

Allergy or
Hypersensitivity to
Food

A dog may or may not
be allergic;
commonly a reaction against a protein, rarely an additive;
clinically indistinguishable from atopy, which is inflammation caused
by an environmental allergy.

The condition is treated with an elimination diet, where the diet is
reduced to a simple protein and carbohydrate such as chicken and rice.
Once improvement is seen ingredients are added back in until the
culprit can be determined. Symptoms are treated with
antihistamines, the addition of fatty acids to the diet and
glucocorticoids for inflammation.

Atopy
(hypersensitivity to
allergens in air)

Atopy is a
hypersensitivity to
aeroallergens such as pollens, house
dust mites, or mold spores. Allergy related problems could vary with
the change in seasons.

Dog ear atopy is diagnosed using a dog's history, a physical exam and
by ruling out other possible causes for the condition. The veterinarian
might perform an allergy skin test to identify the specific allergen
that is causing the problem.

Treatment can include allergy shots to reduce the level of sensitivity
(called immunotherapy), adding fatty acids to the diet and topical
glucocorticoids to reduce inflammation.

Dogs treated for atopy has a good prognosis with treatment, although
the condition often cannot be cured.

Dog Ear Atopy

Changes to Ear Structure and Hair

The ear canal can narrow
(stenosis) as the result of several conditions, trapping debris in the
ear. Conditions include cerumen gland hyperplasia (too many normal
cells formed in the ear) and the formation of polyps.

There are two types of dog ear
infections, those cause by bacterial
and other that are caused by yeast
or fungus. When the problem occurs in the outer or external ear, it
is
referred to as Otitis externa. Depending on the cause, it can be a
challenge to treat, although in most cases, cleaning the ear canal and
applying medications will cure the problem.

Medications used include an antibiotic or antifungal agent as
well as a
glucocorticoid to address the inflammation. The glucocorticoid also
changes the secretion in the glands that line the ear canal, creating
an unfavorable environment for the infectious agent to multiply in
numbers. Most medications are applied as drops since the liquid
is easily distributed in the ear canal.

If a dog ear infection is left untreated, it can spread to the
otitis
media or inner ear, causing problems such as a thinning of the tympanic
membrane. Problems such as ulceration can extend all the way to the
eardrum.

Once the disease progresses to this point, it is more
difficult for the
veterinarian to break the cycle of inflammation, ulceration, infection
and issues which start to destroy surrounding structures in the ear.
Over time hearing can decline such as the inability to hear high
pitched sounds. A dog can experience pain as well.

Problems can occur if the eardrum ruptures allowing infectious
agents
to spread to the other side. Once treated a veterinarian has to make
sure that the eardrum doesn't heal before the infection is eliminated,
or it can become trapped.

Foreign Bodies

During the spring and summer
grass seeds or plant awns are a common cause, particularly in breeds
with longer hair around the ears. The foreign body is found during an
in office examination using a device called an otoscope. Once the
foreign body is removed, ear health should be restored.

Genetics

There are several inherited
problems can result in dog ear illnesses and abnormalities. These include:

Stenosis: a constriction or narrowing of the ear duct

Hirsutism: heavy hair growth which blocks normal air flow
into the ears or that traps moisture

The
spontaneous form of hyperadrenocorticism or Cushing's
Disease is an excessive production of glucocorticoids either
due to a microadenoma (small tumor) or macroadenoma (large tumor) of
the pituitary gland or due to adrenocortical neoplasms (non cancerous
tumor that forms from the cells lining the outside of a tumor.

The condition is diagnosed with several blood tests and a urinalysis.
X-rays are used to check the adrenal glands and for osteoporosis.
Ultrasound can also check the adrenal gland.

Medications are used to treat the disease depending on the type of
hyperadrenocorticism diagnosed. It may be necessary to remove the
adrenal gland if tumors are present (neoplasia).

The prognosis for 60% of dogs with adrenal tumors is a life expectancy
of 36 months.

Hypothyroidism

Hypothyroidism
is caused by
insufficient production of thyroid hormone. Diagnosis is reached using
blood tests and thyroid tests for free T4, total T4 and TSH assays
among others.

Hypothyroidism in dogs is treated with hormone replacement therapy. The
prognosis is good for dogs that achieve remission by taking the
recommended medications.

Keritinization Disorders

Keritinization disorders in the
ears turn normal squamous skin cells into a horny material such
as nails.

Medication

Certain topical drugs can
irritate and injure the ears. Abrasive cleaners can also cause
irritation.

Moisture

Moisture in the ears can create
the conditions that lead to bacterial infections. This can occur as the
result of swimming, the use of the wrong dog ear cleaning products,
living in a high humidity environment and dog owners that clean the
ears too often.

Neoplasia
(tumors)

Neoplasia
is the abnormal
proliferation of cells in the ear can cause an obstruction. Other types
of obstructions are polyps cerumen gland hyperplasia (increase in the
number of normal cells in the glands that line the ear).

Dog ear tumors are diagnosed with an examination using an otoscope.
Treatment involves surgical removal of the cancerous area. The
prognosis is good if the cancer is completely removed.

Parasites

Several types of parasites
can
cause dog ear illnesses. This includes:

Otodectes cynotis (ear mites): Looks like coffee grounds in
the ears. The mites are diagnosed via an examination in the
veterinarian's office with a tool called an otoscope.

The veterinarian will evaluate ear debris under a microscope to confirm
the diagnosis. The condition is treated with a medication that
kills parasites using an oral or topical medication.

Scabies: dog ear scabies are a highly contagious disease
caused by Sarcoptes
scabie var.canis in dogs also known as parasites or mites. The
disease usually effects the edges of the ears as well as the ear canal.

The veterinarian will diagnose the condition after examining
superficial skin scrapings. If scabies are suspected, a positive
reaction to treatment will confirm the diagnosis. Antiparisitic
agents are used to treat the condition.

Dog Ear Scabies

Otobius megnini: a soft bodied tick

Pemphigus
foliaceus
(immune-medicated skin diseases)

The skin disease Pemphigus
foliaceus causes blistering on the ears. The condition can be
induced by drugs or as the result of a tumor. The condition often
occurs on the inner surface of the ear.

Pemphigus in the ears is diagnosed using a biopsy. The condition is
treated with immunosuppression drugs. The prognosis is fair with
treatment. If the pemphigus was caused by a medication your dog is
taking, making a change results in an excellent prognosis.

Pemphigus Foliaceus in Dog
Ear

Seborrhea (idiopathic seborrhea)

Idiopathic seborrhea
(unknown
cause) is the excessive formation of ear wax. It causes an abnormal
change in the cell renewal time, causing too many skin cells to form.

The condition is diagnosed with a biopsy.

Dog ear seborrhea is treated with ear cleaners and corticosteroids and
retinoids. The prognosis is guarded for dogs with this condition.

Vestibular Disease

In dogs, the vestibular or inner
ear provides the dog's brain with information on body position. It
informs the dog if it is turning, falling, or speeding up. This
information coordinates with information from the eyes and other
sensory information such as touch to help a dog maintain balance.

Dog With Vestibular Ear Problem

Dog Vestibular Disease Patient that "couldn't walk straight."

Symptoms of dog vestibular disease:

stumbling

lack of coordination

staggering

head shaking

motion sickness

vomiting

sleeping on hard surfaces instead of bed

Treatment depends on the underlying cause/diagnosis. It can caused by a
treatable inner ear disorder such as a dog ear infection or it is
possible that the cause cannot be determined, called idiopathic
vestibular disease.